Listed below are the 4 most crucial components a pit bike must have before purchasing it either on-line or offline.
Suspension -Forks and Rear Shock 4.
Rims The frame must be made of at least Chomolly steel, Not Mild steel.
Mild steel is too weak even if it has welded brackets it will still snap.
It must have a minimum 2 tube support backbone and be reinforced top and bottom.
Good example of this is the SDG frame which is over 4 years old but very strong almost indestructible.
The latest fame on the market is the Trellis frame.
Basically it has 2 main support beams top and bottom then its joined together with criss cross beams bit like a bridge.
The engine is the donkey.
Its the business end of the bike.
I highly recommend the Lifan engine for non racing and amateur riders.
It's proven, tested and stacks up to a lot of punishment.
The 125cc to 160cc has a all up gear box and extensive research and development over many years makes this engine stable in the market place.
Suspension being the front forks and rear shock I recommend Coil & oil shocks.
46mm front forks are basically the normal issue on a mid range pit bike.
The rear shock must be able to take least 100kg.
A good way to test this is sit on the back of the bike and see if it isn't to bouncy.
If its firm then its OK for to start off.
You can upgrade to fast ace rear shocks.
I suggest the fastace 1000 pound AR-66c for single rear swing arm setup not A- frame.
Rims is a component which is always overlooked because new buyers do not know that your rims are like your drive train a car.
It needs to be strong or you won't get the power to the ground.
Where most rims fail is the design does not cope with the power the engine puts out.
You need minimum 32 spoke Billet style rims.
This is because the rear takes all the power and drives the bike forward.
The hub design in the the billet style is a excellent designs as it fans out the spokes and distributes the energy to the outer rim evenly instead of directly vertical.
So know you know when you go to buy a bike on eBay look for a reinforced frame with at least two support beams, the engine is Lifan 125cc-160cc displacements, the suspension is 46mm upside down forks and adjustable rear up to 100kg and the rims are minimum 32 spoke with billet style hubs.